The present invention relates to a starting and operating device for controlling the starter that ignites a sodium lamp.
Known in the art, there is the U.S. Pat. No. 4,896,077 of Peter G. DODD, granted on Jan. 23, 1990. This patent describes an ignitor disabler for disabling the ignitor of a high intensity discharge lamp. This ignitor disabler monitors the operating or characteristic voltage of the lamp.
This ignitor disabler comprises means for disabling the igniting portion during abnormal lamp operation; means for triggering the means for disabling after passage of a predetermined amount of time, the means for triggering having a timing component for measuring the predetermined amount of time, which timing component begins time measuring operation only under certain predetermined conditions; means for resetting the timing component of the means for triggering upon lamp ignition; and means for establishing a threshold voltage that is higher than the characteristic voltage of the lamp under normal operating conditions. An object of this invention is to provide a unit that is substantially independent of the ballast/ignitor and can therefore be used in conjunction with any standard ballast/ignitor currently commercially available for these lamps.
Even if the problem of providing a unit that is substantially independent of the ballast is specifically aimed in this patent, this goal is not substantially reached because the power supply of the disabler described in this patent is designed to convert alternating current from the ballast secondary winding to direct current. As there are different ballasts operating at different powers on the market, the voltage available at the ballast secondary winding varies from one ballast to another. Therefore, the object of providing a unit that is independent of the ballast is not reached by this circuit.
Also known in the art, there are the U.S. Pat. No. 4,853,599 of Santiago SINGARAYER, the U.S. Pat. No. 4,473,779 of Larry A. LINDNER and the U.S. Pat. Nos. 4,810,936 and 4,763,044 of Joe. A. NUCKOLLS that provide different circuits that can be used for protecting the ballast-starter of a high intensity lamp. One of the drawbacks with the above-mentioned patents resides in the fact that all of these devices cannot be used in conjunction with different ballast-starters commercially available on the market.